I know some use grease, dad's Brylcreem, and some other methods, I will suggest something different. What I have found the best, is a commercially available spray. It is Red, probably to see the area protected. I buy it at auto parts stores, just spray the newly cleaned connections, covering it completely, up, down and all around.
By using this product, you can simply wipe it off with a rag, work on it and re-apply.
With the battery-(ies) covered, we sometimes neglect not only the water level, but the terminals as well, then some day we will have trouble, and find corrosion and poor connections.
End of lecture.
Ozz
'07 3400RL 2nd RTU
2 Golf Cart batteries 3,000 watt inverter, automatic transfer switch
Honda 2000 Generator, Maytag's with 220 Dryer
Stationary domed Sat. dish, LCD 12 Volt Amp gauge, LCD Tank Monitor
3 added 120 volt outlets, On Board Air; 12 Volt Viair 450C compressor
2006 Ford PSD 4x4 Off Road Lariat, Hadley Air Horns, Truck inverter with 110 volts: laptop, Color Backup camera, Firestone air bags,Husky air ride roller hitch, Awning lock